Draft regulator



Feb. 28, 1956 A H, ZIPH 2,736,500

DRAFT REGULATOR Filed Nov. 26, 1952 l -una United States Patent DRAFT REGULATOR Andrew H. Ziph, St. Joseph, Mo., assignor to Walker Manufacturing and Sales Corporation, St. Joseph, Mo., a corporation of Missouri Application November 26, 1952, Serial No. 322,596

1 Claim. (Cl. 236-45) This invention relates to new and useful improvements in draft regulators for combustion apparatus, and has particular reference to draft regulators of the adjustable type which, once set for the desired draft, will automatically maintain the desired draft despite variations in the natural r stack draft. Certain combustion apparatus, notably yoil burners of certain types, is quite sensitive to magniture of draft, and requires substantially constant draft for efficient operation. In general, this type of draft regulator contemplates a draft relieving opening in the ue pipe or stack connection of the combustion apparatus, said opening being regulated by a damper which is movable responsively to variations in the stack draft to admit greater or smaller quantities of air.

The principal object of this invention is the provision of an improved draft regulator of the type described employing an adjustable counterweight carried by the damper member. n

Another object is the provision of a draft regulator of the character described having novel indicator means whereby the setting thereof may be readily observed from any angle.

A further object is the provision of a draft regulator of the character described having novel frictional means for holding it at any desired position of adjustment.

Other objects are simplicity and economy of construction, dependability and eciency of operation, and applicability for use with many types of combustion apparatus.

With these objects in View, as well as other objects which will appear in the course of the specification, reference will be had to the drawing, wherein:

Fig. l is a front elevational view of a draft regulator embodying the present invention, shown in tsclosed position.

Fig., l is a sectional view taken on line II-II of Fig. l.

Fig. 3 is a fragmentary sectional View taken on line III-III of Fig. 2.

Fig. 4 is a fragmentary sectional view taken on line IV-IV of Fig. 3.

Fig. 5 is an enlarged fragmentary sectional View taken on line V-V of Fig. 3.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies to a horizontal pipe adapted to be interconnected at one end in the flue pipe or stack connection, not shown, of a combustion apparatus, and carrying the draft regulator, designated generally by the numeral 4, at its opposite end. Said regulator includes a cylindrical ring 6 inserted telescopically into pipe 2, said ring having an outwardly extending annular ange 8 which limits the insertion of said ring into said pipe, and an inwardly extending annular flange 10, the inner edge of which defines a circular air inlet opening 12. Said opening is normally substantially closed by a circular damper door or blade 14. Said blade is pivotally supported in said opening by a pair of pivot pins 16. Said pins are horizontal and coaxial, being dis- ICC posed in the plane of the blade and above the center thereof. Each pin is fixed at its inner end in blade 14, and is pivotally mounted at its outer end in socket members 18 stamped from flange 10 of the ring.

The axis defined by pivot pins 1,6 divides blade 14 into an upper or minor segment and a lower or major segment. It is apparent that the current of air against the outer face of the blade induced by the draft vacuum within pipe 2 will cause the lower segment to swing inwardly, thereby partially uncovering opening 12 and admitting air to pipe 2 and thence to the Hue pipe, not shown, thence partially relieving the draftin the combustion apparatus. The movement of the blade will be substantially proportional to the stack draft, and the combustion chamber' draft will thus be maintained substantially constant despite variations in the stack draft. The lower portion of blade 14 is prevented from swinging forwardly from the plane of opening 12 by a stop plate 20 (Figs. l and 3) welded or otherwise fixed to the inner surface of flange 10 and overlapping the inner face of the upper segment of the blade adjacent one of pivot pins 16. A portion of said stop plate is offset inwardly from said pivot pin and forms a shoulder 22 adapted to be engaged by the lower segment of the blade when said blade has swung open to an approximately horizontal position, thereby to limit said opening movement.

Adjustment of the regulator for maintaining different drafts is accomplished by means of the mechanism detailed in Fig. 5. A tubular sleeve 24 is fixed at its forward end in blade 14 above pivot pins 16. Said sleeve is disposed at right angles to the plane of said blade, and extends rearwardly therefrom. A screw 26 with multiple threads is carried by the sleeve.v Said screw is disposed inwardly from the blade, and has a reduced cylindrical portion 28 carried rotatably in sleeve 24, the shoulder 30 formed on said screw by said reduction bearing against the rearward end of said sleeve. At the forward end of cylindrical portion 28 the screw is still further reduced in diameter to form a threaded extension 32 which extends forwardly from the plane of blade 14. A spring washer 34 is disposed on said extension and bears on shoulder 36 of the screw. Disposed on said screw extension forwardly of washer 34 is a larger washer 38 of felt or other suitable yieldable and resilient material, then a planar pointer linger 40 having a hole 42 formed therein fitting loosely but non-rotatably over the screw extension, said linger extending radially from said screw, and finally a knurled adjusting knob 44 threaded on said screw extension.v When said knob is tightened, felt washer 38 is compressed against the forward face of blade 14 and the forward end of sleeve 24, thereby frictionally loading the screw against turning. The frictional turning load may be adjusted by turning knob 44 on the screw extension. Y

A planar, segmental weight 46 is carried on screw 26 in parallel relation to blade 14, said weight having a press-fitted insert 48 internally threaded to engage the threads of screw 26. Said weight is movable toward and from the blade by turning knob 44. Said weight is prevented from turning with said screw by means of a rod 50 threaded or otherwise xed in said weight in spaced relation from screw 26 and extending forwardly in parallelrelation to said screw through a hole 52 formed therefor in blade 14, and thence forwardly adjacent knob 44 within the orbit of indicator linger 40, thereby limiting the turning of knob 44 to approximately one revolution. The threads of screw 26 are of sufficiently long lead that the entire desired adjustment of the weight therealong may be obtained with one revolution of the screw.

The weight of the upper or minor segment of the blade, plus the parts carried thereby, is less than the weight of the lower or major segment of the blade, whereby the stiifen the blade.

blade always return to its closed or vertical position,

as shown in Fig. `2; Further, the parts are so proportioned that when the blade is closed, and weight 46 disposed in its closest relation to the blade, as in Fig. 2, a very slight clockwise moment is exerted on the blade, tending to hold it closed. This setting should correspond to the minimum draft which will be required at the combustion apparatus, and may actually closely approach actual balance of the blade. It will be noted that portions 54, 56, and 5S of the blade are offset forwardly from the principal plane of the blade. These offsets may be decorative, and serve to Furthermore, since the olfsets are forward of pivots 16, they'serve to counterbalance partially the weight 46, which is to the rear of the pivots, thereby permitting a closer approach to actual vertical balance of the blade. The offset 5%, which corresponds in shape to Weight 46, also serves to permit a closer approach of said weight to the principal plane of the blade.

It is obvious that when knob 44 is turned to move weight 46 rearwardly along screw 26, the clockwise force moment of said weight (as viewed in Fig. 2) is increased, whereby a greater draft will be required to swing the blade to an open position, and a greater draft will be maintained at the combustion apparatus. The setting of the weight is indicated both by the angular position of indicator finger 40, which may be read relative to suitable indicia 6%) imprinted on the face of the blade, or by the degree of extension of rod 50 forwardly from the blade. The rod may have graduations thereon for facilitating the latter reading. This double indicating means permits setting of the weight, and visual indication thereof, either from the front or from the side, as may be necessary or desirable in any given installation. In certain installations in relatively inaccessible places, it is not possible for the operator to obtain an unobstructed face view of the regu lator. Rod S0 is of such length that it projects into the path of indicator finger 40 even when weight 46 is at the rearward limit of its movement on screw 26. Said rod thus limits the turning of the screw to about one revolution, and prevents said screw from being turned so far as to disengage the weight completely therefrom.

A bolt 62 and nut 64 is secured in blade 14 adjacent the bottom edge thereof. It is useful in installations where pipe 2 is interconnected in a vertical ue pipe, and where pipe 2 is so short that blade 14, when open, extends into the path of the gases in the ue pipe. In such installations, the upward ow of flue gases impinges on the blade and tends to disturb the setting of the blade for the desired draft. Bolt and nut 62,-'64 counteract this effect..

While I have shown and described a specific embodiment of my invention, it 'is apparent that many minor changes of structure and operation could be made with-- out departing from the spirit of the invention as defined by the scope of the appended claim.

What I claim as new and desire to protect by Letters Patent is:

A draft regulator for combustion apparatus comprising a frame having an opening therein, a circular blade of a. size to substantially completely lill said opening, said blade being pivoted to said frame within'said opening on an axis lying in the plane of the blade and subtending an arc of less than degrees thereof, whereby said blade is divided into major and minor segments, a weight carried by the minor segment of the blade,y means for moving said weight toward and from said blade, said last means including a tubular sleeve fixed in said minor blade segment normally to the plane thereof, a screw threaded insaid weight and having a portion of reduced diameter rotatably mounted in said sleeve, an adjusting knob mounted on that portion of said screw at the side of said blade opposite the side on which said weight is disposed, whereby longitudinal movement of said screw is prevented, a radially extending indicator linger mounted on said screw in fixed angular relationship theretoy adjacent said knob, and a rod-like member secured to said weight in spaced relation to. said screw and extending parallel thereto, said member extending slidably through an aperture formed therefor in said blade and into the path of said indicator finger, whereby said member serves to limit the turning motion of said screw, and whereby the distance of extension of said rod-like member through said blade indicates the position of said weight on said screw.

References Cited in the le of this patent UNITED STATES PATENTS vrp@ ...da w., 

